The present invention relates to a thermoplastic resin composition. More specifically, the present invention relates to a thermoplastic resin composition comprising a polypropylene and a polyphenylene ether, which composition has a superior balance between its heat resistance and its impact resistance. The composition can be suitably used in an electric field, an electronic field, a car field and others including fields of various industrial materials.
As disclosed in JP-A 62-223217, JP-A63-113058, JP-A 63-225642, JP-A 3-227361 and JP-A 3-231945, a resin composition comprising a polypropylene and a polyphenylene ether is known.
More particularly, JP-A 62-223217 discloses a thermoplastic resin composition, which can be obtained by blending a polyphenylene ether, a modified polyolefin composition and an epoxy compound, and which has a superior heat resistance, mechanical properties and processability.
JP-A 63-113058 discloses a thermoplastic resin composition, which can be obtained by blending (i) a polyolefin, (ii) a polyphenylene ether, (iii) a polymer having both a polymerized chain of an alkenyl aromatic compound and an aliphatic hydrocarbon chain in the polymer molecule, and (iv) a diamide compound, and which has a superior balance in mechanical properties, molding processability and solvent resistance.
JP-A63-225642 discloses a resin composition comprising a polyolefin resin, a polyphenylene ether resin and a partially hydrogenated alkenyl aromatic compound-conjugated diene block copolymer, which composition has a particularly superior balance in mechanical properties such as rigidity, and has a superior molding processability, oil resistance and chemical resistance.
JP-A 3-227361 discloses a resin composition, which can be obtained by melt-kneading a polyphenylene ether, a polyolefin and a specific functional compound, and which has a particularly improved impact resistance.
And JP-A 3-231945 discloses a resin composition, which can be obtained by blending (i) a melt-kneaded product among a polyolefin, a polyphenylene ether and a specific functional compound and (ii) a specific polar compound.
However, each of the above-mentioned resin compositions does not have a superior balance between its heat resistance and impact resistance, while a thermoplastic resin composition comprising a polypropylene and a polyphenylene ether, and having a superior balance between its heat resistance and its impact resistance has been desired.
An object of the present invention is to provide a thermoplastic resin composition comprising a polypropylene and a polyphenylene ether, which is superior in balance between its heat resistance and its impact resistance.
The inventor of the present invention has undertaken studies to develop a thermoplastic resin composition comprising a polypropylene and a polyphenylene ether, which has a superior balance between its heat resistance and its impact resistance. As a result, it has been found that a combination of a specific ethylene-xcex1-olefin copolymer with a polypropylene and a polyphenylene ether, or further a combination of a specific ethylene-xcex1-olefin copolymer with a polypropylene, a polyphenylene ether and a compatibilizer can give a thermoplastic resin composition having a superior balance between its heat resistance and its impact resistance, which composition has a superior flowability due to the polypropylene, and a superior heat resistance and rigidity due to the polyphenylene ether. Thereby, the present invention has been obtained.
The present invention provides a thermoplastic resin composition comprising:
(i) 30 to 94% by weight of a polypropylene (A),
(ii) 5 to 69% by weight of a polyphenylene ether (B), and
(iii) 1 to 50% by weight of a copolymer (C), provided that a total weight of the components (A), (B) and (C) is 100% by weight, wherein the copolymer (C) has a molar ratio of a structural unit derived from the xcex1-olefin represented by the following formula (I) to a structural unit derived from ethylene of not less than (0.8/(3n +2))/1,
CH2=CHxe2x80x94(CH2)nCH2CH3xe2x80x83xe2x80x83(I) 
wherein n is an integer of 0 to 10.
Further, the present invention provides a thermoplastic resin composition comprising:
(i) 30 to 94% by weight of a polypropylene (A),
(ii) 5 to 69% by weight of a polyphenylene ether (B),
(iii) 1 to 50% by weight of a copolymer (C), and
(iv) a compatibilizer (D) in an amount enough to compatibilize the above component (A) with the component (B), provided that a total weight of the components (A), (B) and (C) is 100% by weight, wherein the copolymer (C) has a molar ratio of a structural unit derived from the xcex1-olefin represented by the above-mentioned formula (I) to a structural unit derived from ethylene of not less than (0.8/(3n+2))/1.
Still further, the present invention provides a thermoplastic resin composition obtained by melt-kneading:
(i) 30 to 94% by weight of a polypropylene (A),
(ii) 5 to 60% by weight of a polyphenylene ether (B),
(iii) 1 to 50% by weight of a copolymer (C), and
(iv) a compatibilizer (D) in an amount enough to compatibilize the above component (A) with the component (B), provided that a total weight of the components (A), (B) and (C) is 100% by weight, wherein the copolymer (C) has a molar ratio of a structural unit derived from the xcex1-olefin represented by the above-mentioned formula (I) to a structural unit derived from ethylene of not less than (0.8/(3n+2))/1.